Hong Kong’s leader, Carrie Lam, has refused to clarify how journalists can avoid breaking the vaguely defined national security law following the raid and prosecution of journalists at a pro-democracy newspaper.

At a regular press conference on Tuesday the city’s chief executive, Carrie Lam, defended the arrest of senior Apple Daily executives under the national security law (NSL) – two of whom have been charged with conspiracy to commit collusion with a foreign country – as well as the raid of its newsroom and freezing of assets.

Apple Daily has said it will cease online publication this week unless its assets are unfrozen. On Tuesday it closed its English edition.